


Truemate(s)

by VampAmber



Series: SPN ABO Bingo: Round One [6]
Category: Supernatural
Genre: Alpha Dean, Alpha/Beta/Omega Dynamics, Alternate Universe - College/University, Castiel and Jimmy Novak are Twins, Complete, Domestic Fluff, First Kiss, First Meetings, Fluff, Implied Sexual Content, Light Angst, M/M, Mpreg, Omega Castiel, Omega Jimmy Novak, One Shot, SPN A/B/O Bingo, Scenting, Sibling Incest, True Mates, Twincest
Language: English
Status: Completed
Published: 2017-08-20
Updated: 2017-08-20
Packaged: 2018-12-17 12:48:34
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,983
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/11851905
Author URL: https://archiveofourown.org/users/VampAmber/pseuds/VampAmber
Summary: Castiel and Jimmy were twins, and even before presenting and instantly bonding, it was obvious they were truemates. It didn't happen often, but it wasn't unheard of for close relatives to be truemates. It was unheard of for two omegas (or two alphas) to be truemates, though, but what can you do?It wasn't until they went off to college and met Dean Winchester that that final piece of the puzzle fit together and everything made sense.





	Truemate(s)

**Author's Note:**

> So, my very first DCJ fic. I've been addicted to this OT3 for quite a while now, but it took a bingo square to get me to finally write for it. Hopefully I did an okay job?
> 
> I'm a bit stressed right now because the artist picks for DCBB are going on this weekend and I screwed up my summary hard. Everybody keep your fingers crossed for me that I get an artist that actually wants me and not just someone who did it for pity cuz no one else would. Bleh...
> 
> Anyway, the square I used for this fic was **Dean/Cas/Jimmy** (obviously).
> 
> Enjoy! ^_^

From the very beginning, Jimmy and Cas had been close. Almost too close, even for identical twins. They weren't asocial, far from it, but they only made friends as a pair, they only socialized as a pair. They only existed as a pair. There was never Jimmy or Cas, just _JimmyandCas_.

They would throw tantrums when forced into separate beds, so their parents finally gave up and bought them one big bed to share. It was no surprise when they presented that they instantly bonded as truemates (it was rare, but sometimes truemate bonds would happen between family members). The only surprising part was that they both presented as omega. It was practically unheard of, truemates existing between same secondary gender pairs. But there was nothing technically wrong, so they mostly just ignored their strangeness and went about life normally.

When it came time for college, they managed to find one that not only had a good English department for Jimmy, but a good history department for Cas. They may have been absolutely inseparable, but they were actually quite different from each other, personality-wise. Cas was an introvert whereas Jimmy was an extrovert. Jimmy went on Cas’ runs with him but didn't enjoy them as much as his twin did, but it evened out with all the movies Cas would watch with Jimmy even though he wasn't a fan. Jimmy loved classic rock, while Cas enjoyed classical. Identical on the outside, but still different people. Going to college helped them finally branch out and be those different people, but they remained just as close, if not closer.

The trouble, so to speak, started on a random Wednesday afternoon. Cas’ final class of the day had been cancelled because the teacher was sick, so he was rushing across campus to meet up with his brother for an unexpected but welcome late lunch. He heard his cell phone chirp, letting him know he had a text message, so he was looking at his pocket as he reached for his phone instead of where he was going. Before he knew it, he was in a people pile on the ground, with someone struggling underneath him.

“Hey, watch where you're going, man,” the person grumbled. “You could freaking hurt somebody.”

“Oh, I’m so sorry,” Cas said in a rush, struggling to untangle himself so that he could help the stranger up. “I wasn't paying attention to where I was going.”

“Yeah, that part was kind of obvious,” the guy joked when they were finally both upright again. Cas looked over at him and was met with the most amazing green eyes he had ever seen. His heart thumped, and he could see that the other person seemed to be affected as well. No, no, no…

“I'm, uhh… I’m Dean. Winchester. Dean Winchester,” he stumbled out, holding out his hand nervously. But then he smiled and Cas’ heart thumped again, causing the omega to panic.

“I gotta go,” Cas said as he started running, glad that his speed was enough that the Dean guy probably wouldn't be able to catch him.

“I’ll see you around?” Dean called after him, but Cas didn't respond, couldn't respond.

When he was only a block away from the cafe Jimmy loved and was currently waiting for him at, Cas stopped running and leaned against the wall of a clothing boutique. No, this couldn't happen, it was all wrong, because Dean had smelled… like Jimmy, like mate. But that wasn't possible. Their parents had even went to the effort of getting them checked when they’d bonded as children. Jimmy was his truemate. Period. But Dean had smelled…

It took a few minutes for Cas to calm down enough to head towards the cafe. Jimmy stood up and waved him over as soon as he entered, and pulled him in for a hug when he reached the table. “What took you so long, Cas?” He asked as they sat down. “And why do you look like you just saw great aunt Naomi in her underwear?”

“I…” Cas started to say, but stopped as the tears welled up.

“Cas, what's wrong?” Jimmy said, all worry as he pulled his twin in for another hug. “What happened?”

“I ran into somebody,” Cas said through his sniffles. “And he… he…” Cas took a deep breath before continuing, and whispered “...smelled like mate.”

Jimmy just stared at him in shock. “You… you had to have smelled it wrong, you had to…”

“It was that same feeling I get when I scent you,” Cas said softly.

“Had to be a mistake,” Jimmy reassured him, rubbing Cas’ shoulder in a calming manner, just like he always did when his brother, his truemate, was upset.

“Yeah, you're probably right,” Cas agreed, though he wasn't confident.

~~~

The next day, Jimmy was in the library, reaching for a book he needed for one of his classes, when he felt someone come up behind him. “Hey, sorry about yesterday. Not sure what freaked you out so bad, but if it was my fault, I apologize.” Jimmy turned around to meet green eyes. “I’d, uh… like to make it up to you, if you’d let me?”

“You're him,” Jimmy gasped, right before he was hit with the scent of mate. Cas had been right, apparently.

“Who?” The guy, who was obviously Dean, just looked confused.

“The guy that Cas ran into yesterday,” Jimmy explained, not that it cleared anything up for Dean.

“Who’s Cas?” Dean asked.

“My twin brother,” Jimmy said, and finally Dean looked like he understood. But then, after a few moments, he looked even more confused than before.

“Your twin?” Dean asked, and Jimmy nodded. “But… you guys smell the exact same.”

“We do?” Jimmy had always figured that they smelled really similar, their friends had even pointed out how similar on a few occasions. But there had always been differences, too. No two people ever smelled the exact same.

“Yeah, that's why I thought you were him,” Dean said as he ran his hand through his hair. “I smelled you from two rows over, and wanted to apologize to him, but maybe I was wrong? About the scent, I mean.”

No two people ever smelled the exact same, unless… “Wait!” Jimmy said excitedly, before getting shushed by no less than four different library patrons. He ducked his head in acknowledgement and said in a much lower voice, “I think I read something about this once. It was in a really old book from the library when I was a kid, a thing of fairy tale like stories.” If that was it, it finally all made sense.

“So, fiction?” Dean asked, sounding like he was starting to doubt Jimmy’s sanity, or at least his own for listening to this.

“Yeah, but those old stories always had a grain of truth in them somewhere,” Jimmy said smugly. When Dean still looked doubtful, he sighed, glad that his brother wasn't here to tell him he was being overly dramatic. “Trust the English major bibliophile,” he teased, and couldn't hold in his smile when Dean’s expression went from confused to appreciative. Jimmy had to stop himself from enjoying the sensation too much, because it made him feel like he was cheating on Cas. He could now completely understand why his twin was such a mess after encountering Dean the day before.

“Okay then, I’ll bite. What's your theory?” Dean smiled, and Jimmy had to hold in an unknown noise that he at the very least knew would be embarrassing.

“Don't wanna explain it twice,” Jimmy replied, grabbing Dean's hand and trying to not think about how well it fit with his. He really hoped he was right, because otherwise… “Cas always studies at the same coffee place on Thursdays. Come on.” He started dragging Dean, who took the hint quickly and followed the eager omega.

When they reached the quaint little hole in the wall, as Jimmy always called it, he tried to not notice how he had been holding Dean's hand the entire way there. It felt just as perfect as holding his brother's, and that seemed wrong somehow. He wasn't much for praying, but he sent one up anyway that they could get all this figured out, and fast. He reluctantly let go of Dean's hand and ignored the small whimper the other man out as he opened the door. The little bell jingled, and Jimmy's eyes went straight to his twin, who was hunched over his laptop deep in thought.

“Hey, Cas?” Jimmy said as he walked up. He let out a giggle as his brother jumped, startled. “Lookie what I found.” He pointed at Dean, who was still standing over by the door, looking beyond confused.

Cas yelped. “Jimmy, why?” He looked and sounded hurt.

“I'm gonna explain everything, I promise Cas,” he reassured him. He beckoned Dean over and sat down in one of the empty chairs at Cas’ table. When they were all as settled as they could be, Jimmy smiled. With Dean and Cas both so close to him, he could smell how they both were the same, which only further proved his theory.

He must have taken longer than he thought to start, because Dean asked impatiently “Well?”

“I read a book a bunch of years back that had something like this in it,” Jimmy started, to help Cas catch up with Dean. “It was really old, and had stories that were like fairy tales, but more realistic. Normal people, normal situations, no bibbity bobbity boo, you know?” Cas and Dean both nodded, Cas still looking confused and Dean looking even more impatient. “And one of the stories had truemates. Three truemates. Apparently it was rare as all get out even back then, but it can happen.”

“Yeah, but you said they were just stories,” Dean complained. “Maybe no magic or whatever, but make believe nonetheless.”

But Cas had on his intense concentration face. “I think I’ve heard of something like that before, too,” he finally said softly. When both faces turned in his direction immediately, he scrunched his face up even harder.

“Is he in pain or something?” Dean asked Jimmy.

“No, he’s always done this when he's trying to remember some insignificant thing that he learned forever ago then forgot.”

“It's kinda cute in a weird way,” Dean whispered, sounding as enthralled as Jimmy always felt with Cas.

“Yeah, it really is,” Jimmy said and sighed happily. The longer he was around Dean, the more he was liking the guy.

They stopped their mutual admiration session when Cas finally started speaking again. “It was King Gabriel, back in the thirteen hundreds. His queen was his truemate, but he kept a concubine that he was unnaturally attached to, as was his wife. He would boast that he was such a powerful alpha that he had multiple truemates, but no one believed him. He also boasted at times that he was the archangel that he was named after, or that he was a Norse god in his past life, so it was brushed off as just another interesting anecdote. A documentary I saw last year about his family line mentioned it in passing, but I just brushed it off. But maybe…”

“The story I read mentioned that both of the person's truemates smelled the exact same to him, and if I was blindfolded and couldn't touch you, I’d never be able to tell you apart,” Jimmy added.

“Same here,” Dean agreed.

“Me as well,” Cas said, and they were silent as the information truly set in.

“So, I have two truemates, then?” Dean asked.

“Looks like it,” Jimmy said and grinned. He grabbed Dean's hand, and saw Cas grab the other one.

“Twins,” Dean said with a laugh. “That is seriously all manner of hot.”

They spent the rest of the day talking, learning everything they could about each other. They only stopped when the place closed and they were kicked out.

“You guys need a ride home?” Dean asked as they walked in the direction of the biggest parking lot on campus.

“That’d be great, thank you,” Cas said.

“That car is made of sex,” Jimmy blurted out as they got to Dean's car, one of the few remaining in the lot since it was pretty late by now.

Dean chuckled. “That's my Baby, and yeah, she pretty much is.”

Cas ran his hand reverently along the hood. “Beautiful,” he said and gave Dean a shy smile.

“Glad you both have such good taste,” Dean teased as they all piled into the front seat, since neither twin wanted to be alone in the back. Cas, who was sitting squeezed in the middle, gave Dean directions to their small apartment in between even more friendly talking.

When they pulled into the parking lot, the atmosphere in the car changed. “So, I can, like, walk you guys to the door, of you want?” Dean was obviously nervous, and it was apparently contagious as the twins nodded.

“Well, this is us,” Jimmy said sadly when they stood at their front door.

“Can I ask you guys out on a date? I mean, I guess this kinda goes the way it would normally, just with more people, right?”

“I would love that, Dean,” Cas said happily, and the nervous atmosphere was gone in a flash.

“Hell yeah,” Jimmy said enthusiastically, and they all laughed. They exchanged numbers, and decided that Saturday would be perfect. Goofy smiles were on all three faces by the time they were done.

“I guess I'll head out then,” Dean said, but he hesitated, standing there awkwardly.

Jimmy rolled his eyes a few moments later when he caught on to the reason behind Dean's discomfort. “If you wanna kiss us, just do it.” Cas nodded, and Dean visibly relaxed. But then he looked back and forth between the two, as if trying to decide something far more important than just who to kiss first. Jimmy smiled and said “I was born first” before grabbing Dean by his jacket collar and pulling him in for a kiss. It felt just as amazing as kissing Cas, but it was new and different and if Jimmy moaned a little nobody was going to tell.

When they pulled apart to breathe, Jimmy and Cas both giggled as Dean whispered a very impressed and drawn out “Damn.”

“He has that affect,” Cas said fondly. But before Dean had fully recovered, Cas grabbed his collar the same way his brother had. “My turn,” he said mischievously before pulling him in for a kiss just as passionate as the one before.

Dean actually had to brace himself against the wall when they pulled apart. He let out a frustrated groan, and Jimmy noticed just how tight the guy’s pants now seemed to be. He was in the same boat, especially after watching the kiss between Dean and Cas, so he couldn't judge.

“You two are gonna be the death of me at this rate, but damn am I the luckiest alpha on the planet,” Dean finally said, trying in vain to adjust himself into a more comfortable position. Jimmy smiled at Cas and they both laughed.

~~~

“You know, one good thing about all this is that I can finally tell you two apart every single time,” Dean joked as the three worked seamlessly together in their large kitchen, making dinner.

They had bought the house after they’d all graduated college last year, though they'd been living together since about three months after they met. They’d all been officially mated long before they moved in together, though. Dean was a rather impatient alpha, not that Jimmy and Cas were much better.

Jimmy had found a nice job at a small publishing company, while Cas had the chance to live his dream as a history teacher. It had turned out that Dean had been earning his degree in engineering, and he had been recruited in his last semester by an international corporation that had wanted him badly enough to give him a very nice starting salary indeed. It was mostly Dean's sign on bonus that had paid for the down payment on the house, and the three were thankful for that every day.

“You both still smell the exact same,” Dean continued as he grabbed something from the fridge. “But Jimmy's way bigger than Cas, since he's five months and Cas is only three.”

“If you weren't so virile, we wouldn't be having this problem,” Cas complained playfully as he chopped vegetables, his baby bump still barely showing.

“I didn't hear you complaining at the time,” Dean said playfully, checking the oven.

“Yeah Cas, all I remember hearing was 'harder Dean, oh god, oh god’,” Jimmy said as Dean chuckled, maneuvering himself and his larger baby bump around his twin to get to the sink. They had picked out the house specifically because they had fallen in love with the kitchen, and while it was normally big enough for the three of them, they were technically five right now so things were a teeny bit more crowded than usual.

“Good thing I want a ton of pups,” Dean said as he stirred the contents of a pot. “Since you guys are both way too fertile.”

“It’ll be nice to hear the pitter patter of little feet soon,” Cas said wistfully.

“Ton of crying and dirty diapers first, though,” Jimmy grumbled as he rubbed lovingly at his belly.

“Worth it,” Dean said as he pulled the two into a kind of group hug. “Especially since I get to see my two beautiful truemates all perfect and pregnant at the same time.” He kissed them each on the top of the head.

“I didn't know you had a breeding kink,” Cas said as he went back to the cutting board.

“Naw, I just have a _JimmyandCas_ kink.”

**Author's Note:**

> Normally I hate sounding like I'm begging for comments, but since this was my first foray into the wonderful world of DCJ, I was hoping you guys would be willing to lemme know if I did okay.
> 
> Yes, I really am this freaking insecure.


End file.
